Go (golang) basics

Archived

This page has been archived and will receive no further updates.

Resources:

Code samples
- Errors
  - https://golang.org/src/net/http/server.go
  - https://golang.org/src/io/io.go
Misc
- Go Playground (Online Go interpreter)
References
Style
- Go: Best Practices for Production Environments

Tools

Renaming/refactoring

gofmt -r 'tocXmlNav -> tocNav' -w .

Strings

String formatting

s := fmt.Sprintf("Hello, %s", "world")

String concatenation

newString = oldString + " new stuff"

Convert integer to string

strconv.Itoa(42)

Arrays/slices

Create a slice

tags := []string{}

Append to a slice

tags = append(tags, tag1, tag2, ...)

Get the length of an arrray/slice

len(slice)

Iterate over a slice

for i, tag := range tags {

Drop index if you don’t need it:

for _, tag := range tags {

Check if a value is in an array/slice

found := false
for _, tag := range tags {
    if tag == token.Data {
        found = true
    }
}
if found == false {...

Sort a slice

Sort a string slice

sort.StringSlice.Sort(tags)

Join a slice

strings.Join(tags, ",")

Maps

Create a map

m = make(map[string]string)

Add a value to a map

m["key"] = "value"

Iterate over a map

for k, v := range m {
 fmt.Printf("%s: %s\n", k, v)
}

Or if you only need the key:

for k := range m {

Test if a key exists in a map

http://stackoverflow.com/a/2050629/399105

if val, ok := m["foo"]; ok {
    //do something here
}

Delete an item from a map

delete(m, "key")

Structs

Create a struct

type SomeType struct {
}

Create an instance of a struct

st := &SomeType{}

File I/O

Write to a file

if err := ioutil.WriteFile(pathToFile, data, 0644); err != nil {
    log.Fatalf("ioutil.WriteFile error: %s", err)
}

data is a byte array ([]byte). To convert a string to a byte array:

[]byte(mimetypeContent)

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